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Laskin, Robert A.

Publications and source records attributed to Laskin, Robert A..

13 records
All sourcesNASA NTRSDOE OSTI
NASA NTRS2007

SIM Planetquest Science and Technology: A Status Report

Optical interferometry will open new vistas for astronomy over the next decade. The Space Interferometry Mission (SIM-PlanetQuest), operating unfettered by the Earth's atmosphere, will offer unprecedented astrometric precision that promises the discovery of Earth-analog extra-solar planets as well as a wealth of important astrophysics. Results from SIM will permit the determination of stellar masses to accuracies of 2% or better for objects ranging from brown dwarfs through main sequence stars to evolved white dwarfs, neutron stars, and black holes. Studies of star clusters will yield age determinations and internal dynamics. Microlensing measurements will present the mass spectrum of the Milky Way internal to the Sun while proper motion surveys will show the Sun's orbital radius and speed. Studies of the Galaxy's halo component and companion dwarf galaxies permit the determination of the Milky Way's mass distribution, including its Dark Matter component and the mass distribution and Dark Matter component of the Local Group. Cosmology benefits from precision (1-2%) determination of distances to Cepheid and RR Lyrae standard candles. The emission mechanism of supermassive black holes will be investigated. Finally, radio and optical celestial reference frames will be tied together by an improvement of two orders of magnitude. Optical interferometers present severe technological challenges. The Jet Propulsion Laboratory, with the support of Lockheed Martin Advanced Technology Center (LM ATC) and Northrop Grumman Space Technology (NGST), has addressed these challenges with a technology development program that is now complete. The requirements for SIM have been satisfied, based on outside peer review, using a series of laboratory tests and appropriate computer simulations: laser metrology systems perform with 10 picometer precision; mechanical vibrations have been controlled to nanometers, demonstrating orders of magnitude disturbance rejection; and knowledge of component positions throughout the whole test assembly has been demonstrated to the required picometer level. Technology transfer to the SIM flight team is now well along.

astrometry↗
NASA NTRS1995

Technology for Space Optical Interferometry

Optical interferometers are expected to provide the next great leap forward in space based astronomy beyond the Hubble Space Telescope. Various systems are envisioned, ranging from large orbiting structures to lunar based facilities to separated spacecraft flying in formation. Regardless of the specific architecture, these systems will present unprecedented challenges in the measurement and control of optical surfaces, hence driving the technological state-of-the-art in the areas of laser metrology and alignment and stabilization of optomechanical systems.

interferometry↗
NASA NTRS1995

Technology for Space Optical Interferometry

The Micro-Precision Control/Structure Interaction (CSI) program at JPL is chartered to develop the structures and control technology needed for sub-micron level stabilization of future optical space systems. The extreme dimensional stability required for such systems derives from the need to maintain the alignment and figure of critical optical elements to a small fraction (typically 1/20th to 1/50th) of the wavelength of detected radiation (about 0.5 micron for visible light, 0.1 micron for ultraviolet light). This requirement is common to a broad class of optical sysetms. The challenge for CSI arises when such systems become large, with spatially distributed optical elements mounted on lightweight, flexible structure. This paper will present an overview of the approach that is being taken by JPL's CSI program to address this challenge. In particular, the paper will discuss the application of CSI technology to a specific example of a future large optical space mission. Experimental demonstration of the technology on ground-based testbeds will also be presented.

structures↗
NASA NTRS1993

Study Of Active Vibration Isolators

Report presents study of single-link ibration-isolating active suspensions, used to suppress vibrations in structures or to protect delicate scientific instruments from vibrations generated by nearby machinery. In study, suspensions analyzed in terms of mechanical impedance.

Lurie, Boris J.↗
NASA NTRS1993

Micro-precision control/structure interaction technology for large optical space systems

The CSI program at JPL is chartered to develop the structures and control technology needed for sub-micron level stabilization of future optical space systems. The extreme dimensional stability required for such systems derives from the need to maintain the alignment and figure of critical optical elements to a small fraction (typically 1/20th to 1/50th) of the wavelength of detected radiation. The wavelength is about 0.5 micron for visible light and 0.1 micron for ultra-violet light. This lambda/50 requirement is common to a broad class of optical systems including filled aperture telescopes (with monolithic or segmented primary mirrors), sparse aperture telescopes, and optical interferometers. The challenge for CSI arises when such systems become large, with spatially distributed optical elements mounted on a lightweight, flexible structure. In order to better understand the requirements for micro-precision CSI technology, a representative future optical system was identified and developed as an analytical testbed for CSI concepts and approaches. An optical interferometer was selected as a stressing example of the relevant mission class. The system that emerged was termed the Focus Mission Interferometer (FMI). This paper will describe the multi-layer control architecture used to address the FMI's nanometer level stabilization requirements. In addition the paper will discuss on-going and planned experimental work aimed at demonstrating that multi-layer CSI can work in practice in the relevant performance regime.

Sirlin, Samuel W.↗
NASA NTRS1992

Study Of Space-Based Optical Interferometer

Report discusses calibration and operation of conceptual Focus Mission Interferometer (FMI), consisting of component instruments mounted at widely separated locations on large truss structure in orbit 1,400 km above Earth. Includes six telescopes in linear array. Outputs combined in pairlike fashion so FMI operates as three distinct two-telescope interferometers. Accurate enough for submilliarcsecond astrometry.

Redding, David C.↗
NASA NTRS1992

Optical systems integrated modeling

An integrated modeling capability that provides the tools by which entire optical systems and instruments can be simulated and optimized is a key technology development, applicable to all mission classes, especially astrophysics. Many of the future missions require optical systems that are physically much larger than anything flown before and yet must retain the characteristic sub-micron diffraction limited wavefront accuracy of their smaller precursors. It is no longer feasible to follow the path of 'cut and test' development; the sheer scale of these systems precludes many of the older techniques that rely upon ground evaluation of full size engineering units. The ability to accurately model (by computer) and optimize the entire flight system's integrated structural, thermal, and dynamic characteristics is essential. Two distinct integrated modeling capabilities are required. These are an initial design capability and a detailed design and optimization system. The content of an initial design package is shown. It would be a modular, workstation based code which allows preliminary integrated system analysis and trade studies to be carried out quickly by a single engineer or a small design team. A simple concept for a detailed design and optimization system is shown. This is a linkage of interface architecture that allows efficient interchange of information between existing large specialized optical, control, thermal, and structural design codes. The computing environment would be a network of large mainframe machines and its users would be project level design teams. More advanced concepts for detailed design systems would support interaction between modules and automated optimization of the entire system. Technology assessment and development plans for integrated package for initial design, interface development for detailed optimization, validation, and modeling research are presented.

Shannon, Robert R.↗
NASA NTRS1991

JPL control-structure interaction technology: Micro-precision CSI

The NASA Control-Structure Interaction (CSI) Program is described in outline and graphic form. Particular emphasis is given to the activities of the Jet Propulsion Lab. The goals of the program are (1) controlled structure performance enhancement, (2) controlled structure unified methods for design/analysis, and (3) ground validation methods for CSI flight systems.

Laskin, Robert A.↗
NASA NTRS1987

Space science/space station attached payload pointing accommodation study: Technology assessment white paper

Technology assessment is performed for pointing systems that accommodate payloads of large mass and large dimensions. Related technology areas are also examined. These related areas include active thermal lines or power cables across gimbals, new materials for increased passive damping, tethered pointing, and inertially reacting pointing systems. Conclusions, issues and concerns, and recommendations regarding the status and development of large pointing systems for space applications are made based on the performed assessments.

Lin, Richard Y.↗
NASA NTRS1987

On the inadequacies of current multi-flexible body simulation codes

DISCOS was used to simulate the spin-up of a uniform flexible beam mounted on a rigid spinning disk. The system operated well for the first few seconds but then there was a drastic rise in deflection as the whole system became unstable. Attention is given to the reason for the breakdown of DISCOS and how this affects the simulation results from DISCOS and other multiflexible-body simulation programs. It is found that a formulation option already available in DISCOS will eliminate the dramatic divergence observed in high spin regimes and give good results in low spin regimes while requiring highly simplified input data.

Eke, Fidelis O.↗
NASA NTRS1986

The Softmounted Inertially Reacting Pointing System (SIRPNT)

A softmounted inertially reacting pointing system differs from traditional gimbal-based pointing system architecture in that: (1) the primary pointing control actuator does not need to apply torques on the basebody, and hence will not interact in a destabilizing way with basebody flexibility, and (2) the connection of the payload with the basebody is via a soft, low frequency structure, which acts as a two-way low pass filter for disturbances. Planar, linear analysis of a preliminary design of such a pointing system using the piezoelectric polymer material PVF2 as an active element in the softmount is presented demonstrating the potential performance in disturbance rich environments such as Space Station.

Sirlin, Samuel W.↗